N63T: Improvements to Bosch Spark Plug. Various engine performance symptoms could occur if the spark plug insulator becomes damaged: * The Service Engine Soon (MIL) may be on with rough running and misfire fault(s) stored. * Intermittent performance or rough running without a relevant DME fault stored. The spark plug insulator could be damaged in cases of combustion faults such as misfiring, ignition knock or super knocking conditions.
